After a July-injury to backup catcher, Ramon Castro,the Chicago White Sox called up former prospect Tyler Flowers to play behind A.J Pierzynski. Just a few weeks later, Flowers is now the team’s primary backstop following news of Pierzynski’s broken wrist on Tuesday. The White Sox will likely add a veteran catcher to the mix, but Flowers could – and should – get the lion’s share of playing time down the stretch.

After hitting .270 last season, Pierzynski was hitting .296 with 30 extra-base hits at the time of his injury. With his bat out of the lineup, the ChiSox will rely on their 25-year-old catcher to pick up the lost production. Flowers may not hit for the same high average; however, he does have solid pop (15 minor-league home runs this season and one major league) and will take a walk, something Pierzynski did not do much of (5% walk rate). Flowers walked in more than 14% of his plate appearances at Triple-A this season. He already has three walks in major-league eight games. Because of this, his on-base percentage should not suffer due to the expected struggles in average.

As mentioned, the addition of a veteran is likely; however, the White Sox are better off to give Flowers a six-week audition heading into 2012. Because of the position scarcity and the likelihood for playing time, he could be a nice addition for AL-Only owners down the stretch. On top of the solid OBP, his right-handed power is likely to play up in U.S. Cellular Field, a ballpark that favors right-handed power hitters. Depending on how he handles his latest tour of major-league duty, Flowers could be a catching sleeper for next season as well.

In mixed-leagues, Flowers is an option, but more so in deeper 14-plus team formats. In shallower leagues, Chris Ianetta may be a more attractive option. Ianetta in many ways is a mirror image of Flowers. Both right-handers post above-average walk rates, solid power, and a hole in the bat in terms to contact. The one thing that puts Ianetta ahead is he has produced at the major-league level. Although he is hitting just .237 this season, his OBP is a robust .382 – fueled by an 18% walk rate. He has also popped 12 home runs in 90 games. Ianetta is available in more than half of standard leagues, so if you’re looking to fill Pierzynski’s void or looking to upgrade, check for Ianetta.

Pitchers with good stuff and iffy results can frustrate fantasy owners and scouts alike—just ask the fans of Ivan Nova. On Wednesday, two pitchers with a similar report were promoted from the minor leagues: Henderson Alvarez of the Blue Jays and Garrett Ricahrds of the Angels. Is either worth a roster spot? Let’s take a look.

Alvarez is a 21-year-old righty with groundball tendencies. His fastball can and will get into the mid-to-upper 90s and he complements the pitch with a good changeup. For some reason or another, though, Alvarez has never held a strikeout per nine innings ratio over seven throughout the minor leagues. The American League East is no friend to pitchers, young or old, but rookie pitchers in particular can find the transition from the minors to the toughest division in baseball rude. Just ask Kyle Drabek.

Still, there are some encouraging aspects of Alvarez’s game. His 3.88 strikeout-to-walk ratio in Double-A and 2.86 earned run average are a positive sign, as it’s commonly accepted that the jump from A-ball to Double-A is the toughest a player will face. Even so, Alvarez seems to profile as a back of the rotation starter now unless something clicks. That doesn’t tend to carry a high fantasy value, so abstain from adding him for now.

Richards, on the other hand, is a big righty with a big fastball and good slider. He posted good numbers in the lower minors—not unexpected for a pitcher drafted out of college—but his performance in Double-A has been just okay. His 3.06 ERA and 12-2 record look nice, but a reduction in strikeouts (from 9.4 per nine last season to 6.4) is undesirable.

Unlike Alvarez, Richards is moving into a division that holds two pitching-friendly parks. He still has to face the Rangers, sure, but he will get a crack at the Athletics and Mariners too. Richards feels more likely to have immediate value than Alvarez, if only because of his pedigree, but even then his upside might be a middle of the rotation starter. That does not mean to add him right away, but if you need a spot starter and it’s Richards’ turn to face the Mariners, well, may as well.

In 2009, Robinson Chirinos was a 25-year-old playing A-ball in the Chicago Cubs organization. A converted infielder, he was still new to the catcher position. After years of toiling in the minors, things have progressed quickly since then. Just two years later, Chirinos appears to be the Tampa Bay Rays new primary catcher with a chance to take hold of the position in 2012. Last week, the social media landscape was buzzing about “Honey Nut Chirinos” after the rookie tied a game against the Toronto Blue Jays with a pinch-hit, RBI single in the 11th inning before getting the walk-off hit just an inning later. This came one day after notching four RBI and his first major-league home run.

Despite his age and his inexperience behind the plate, Tampa Bay saw enough potential in Chirinos to make him part of the package of players they received for Matt Garza this offseason. Following a monster campaign at the Double-A level last season (.985 OPS), he quickly captured the attention of a new fanbase with a solid showing in Spring Training. Initially, he struggled this season in Triple-A, but posted good numbers in recent months, showing growth and progress. After a pair of injuries to primary catcher John Jaso – and his replacement Jose Lobaton – Chirinos, 27, finally received a callup following nearly a decade in the minor leagues.

Although they already have a major-league veteran in Kelly Shoppach on the roster, Joe Maddon and the Rays have given Chirinos the bulk of the playing time in Jaso’s absence. Where both Shoppach and Jaso have struggled at the plate this season, Chirinos has provided the Rays with a spark, hitting .286/.362/.405 in his first 16 games. The sample size is small, but production from catcher is difficult to come by.

With Jaso just beginning a rehab assignment and Shoppach unlikely to be retained at the end of the season, the Rays are giving Chirinos every chance to prove he is ready for a larger role heading into 2012. This means playing against both right and left-handed starters. He remains a work in progress on defense; however, his offense thus far looks as advertised.

While his batting average may settle in the .260 area, he shows a disciplined approach at the plate. Because of his refined eye, he should be a safe bet to post above-average walk rates. In doing so, his on-base percentage should be above the norm for a player at his position. With gap power, good on-base skills, and decent wheels for a catcher, Chirinos is a decent mid-tier option in AL-only formats for the rest of 2011 and heading in to next season as well.

For more on Chirinos and information on other impact rookies, check out the Front Office Tool from Bloomberg Sports.

The Astros were one of the league’s busiest teams over the deadline weekend, as they dealt Hunter Pence and Michael Bourn, then demoted Brett Wallace and Chris Johnson to the minors. That leaves the Astros with four players starting at new positions. Tommy looked at Jason Bourgeois on Tuesday, and Carlos Lee is a known quality. Let’s focus on J.D. Martinez and Jimmy Paredes instead.

Martinez is the Astros new left fielder, as Jason Michael has taken over for Pence in right. The soon-to-be 24-year-old is a former 20th-round pick from Nova Southeastern University (that’s in Ft. Lauderdale, Florida, for those unaware). Houston felt comfortable promoting Martinez to the majors despite never touching Triple-A because he hit everywhere he went in the minors, including a .324/.393/.494 line for Double-A Corpus Christi in 577 plate appearances.

Kevin Goldstein of Baseball Prospectus ranked Martinez as the eighth-best prospect in the Astros system, noting that scouts believe he has a good approach at the plate and “outstanding hands” that produce a “quick, quiet swing”. The expectations Goldstein outlines are that Martinez will hit for average, but not much power or speed from a corner outfield spot. Combined with this being Martinez’s first exposure to the major leagues, there is no guarantee he will perform well. Still, if you have an itching for a potential sleeper in batting average, keep an on eye out on Martinez.

Paredes, meanwhile, came to Houston in the Lance Berkman trade last July. He is a switch-hitter who won’t turn 23 until late November and a former second baseman. In Goldstein’s aforementioned rankings, he had Paredes at number six, noting that he could become an everyday second baseman in a perfect world. Paredes is a speedster with a stolen base for every 3.5 games played in the minors (or roughly a 46-steal pace over 162 games), although he could stand to improve on his efficiency, as his career success rate is just 67 percent.

While speed is appealing, the other phases in his game could use some work. Even this season, he was hitting just .270/.300/.426 in Double-A before being called up, and his minor league career slash line is .279/.312/.406. Don’t expect much fantasy value from Paredes outside of steals, and even then, it’s possible he doesn’t reach base or succeed enough to make it worth the effort.

Seeing some young players should be more exciting for Astros fans than watching washed up retreads on a nightly basis, but don’t get too enamored with either in a fantasy setting. Martinez could provide some batting average, however his position limits his value. The same with Paredes, as both lack the power you conventionally see with players positioned at corner spots.

As your league and roster recovers from a fast and furious weekend of deadline moves, you may find yourself looking for some new, uncovered waiver wire gems. With every piece sold by a non-contender, a job opening for someone else becomes available. Here are three players who have value, have a new job, and should be available on most wires.

Jason Bourgeois

The Astros replace the speedy Michael Bourn with…the speedy Jason Bourgeois. In many ways their new centerfielder may look like their old one, but their true talent levels are not the same. Although Bourgeois is hitting .354 on the season, it is in limited duty and his .383 batting average on balls in play (BABIP) will fall with increased playing time. The one true asset he does possess is speed. In 54 games, he has swiped 22 bags in just 27 opportunies. As long as he gets on-base at a decent clip, he should eclipse 40 steals. Now having hitters behind him to covert those steals into runs is another issue.

Chris Davis

Although the Orioles were sellers at the deadline, they did buy low on former Rangers’ prospect Chris Davis. Hours after they did so, they traded away their own first baseman – Derrek Lee – to the Pirates to clear room for Davis in the lineup. At age 25, the slugger has been saddled with the dreaded “Quad-A” label as a player who excels in the minors, but flounders in the majors. In recent seasons this has been true, but Davis did belt 38 big league home runs in part-time work during the 2008 and 2009 seasons. He has 24 home runs in 48 games in the minors this year. While putting it altogether is easier said than done, Davis could be a nice power pick-up for the stretch run.

Dee Gordon

Once the Dodgers traded Rafael Furcal, the Dee Gordon era officially began. The 23-year-old shortstop struggling in his initial callup earlier this summer (.223 batting average in 23 games), but is a top of the lineup prospect with speed to burn. He may not hit many balls over the fence, but can spray them to the gaps, racking up doubles and triples in bunches. After stealing 73 bases in 2009, he swiped another 50 bags last season. Although his first go around with the big league club didn’t last long, he did steal nine bases in 12 chances. Like most prospects, he may struggle at first, but at a position void of stars, he is one to watch.

Although their clubs were sellers, you should consider buying these players.

The White Sox made a big trade on Wednesday, moving Edwin Jackson and Mark Teahen to the Blue Jays for Jason Frasor and Zach Stewart. Shortly after announcing the trade, the White Sox went on to reveal that Alex Rios would be benched in favor of Alejandro De Aza, thus, leaving Rios owners across the land wondering whether they should ditch Rios in favor of De Aza. It’s an unfortunate, but real scenario to ponder.

Let’s start with the basics. Rios is heading to the pine because he is in the midst of a hellacious season. Through 384 plate appearances, he is hitting .208/.255/.300 with only six home runs and eight stolen bases. This from a guy who hit 21 home runs and had 34 stolen bases in 2010. Rios’ power production this season looks a lot like what he did in 2004, but back then he was walking and hitting more singles than he is now. It’s unclear what Rios’ future holds with the White Sox, as he is signed through the 2014 season with an annual average salary over $12 million.

The White Sox recalled De Aza on Wednesday and threw him into their starting lineup immediately. He hit .322/.378/.494 in Triple-A while adding nine home runs and 22 stolen bases. De Aza is probably a new name to many, but this will mark his fourth season with some time in the majors, as back in 2007 and 2009 he saw action with the Marlins, and he appeared in 19 games for the White Sox last season. In 217 big league plate appearances, he owns a line of .242/.286/.325.

That’s not an inspiring effort, but to De Aza’s credit, he has always hit well in Triple-A, with a cumulative .309/.372/.479 offering in 1,100 plate appearances. Some of that came in the Pacific Coast League, which is notorious for inflating offensive statistics, but over the last two seasons he has spent time improving his craft in the Independent League. His game is about contact and speed, and he has at least 20 doubles in each of the last three seasons too.

De Aza isn’t a sure thing to replicate his minor league performances, so tread carefully. If you are a Rios owner, then picking up his replacement might be a smart choice. After all, between the unclear playing time and nasty results so far this season, Rios is unlikely to be scooped up by anyone else in the interim.

A few weeks ago, I warned of the dangers associated with the waiver wire rush whenever a new prospect is called up to the big leagues. In most cases, the new car smell wears off after a few unproductive weeks at the highest level. That said, there are some outliers who can become your team’s best friend.

Dustin Ackley is one of those cases. As a unit, the Seattle Mariners’ offense is putrid – and that is being kind. While the rest of the group offers little-to-nothing in terms of fantasy value, Ackley appears to be a shooting star in an otherwise offensive black hole. He also plays a position – second base – that is void of many above-average producers.

As a whole, second basemen are hitting .256/.317/.379 league wide. Ackley, on the other hand, is hitting .297/.347/.505 in his first 120 plate appearances. While he is clearly hitting better than your average second baseman, his sample size is rather limited. At the same time, there are no signs that his production thus far has been a product of luck or fluke.

Ackley’s .297 may be a bit above his true talent level; however a .319 batting average on balls in play (BABIP) along with a 17.9 line drive rate are both sustainable over a two month period. In terms of power, Ackley’s .207 ISO – or Isolated Power which measures extra-base hit production by subtracting batting average from slugging percentage – ranks second best in the American League at the keystone position behind Robinson Cano’s .213 (minimum 120 plate appearances). The 23-year-old did not show much home run power in the minors, but could reach double-digits this season. Even without balls clearing the fence, his left-handed bat should find plenty of gaps in spacious Safeco Field.

Perhaps the most impressive thing about Ackley’s 30 games in the majors is his keen sense of the strike zone. His walk rate is a tick lower than the average batter, but he strikes out less often which puts his K/BB slightly above the league’s average. In addition to the solid rate stats, he swings at less than 20% of pitches outside of the strike zone (league average is 30% according to fangraphs.com), and makes contact on more than 75% of his swings. Because of this, his swing and miss rate is also very low.

Despite the shallow talent pool, Ackley is owned in just 35% according to Bloomberg Sports’ Front Office tool. The same tool projects him with a .734 OPS for the remainder of the season. While that projection may be a bit harsh, it would still be nearly .40 points better than the league’s average for the position. If Ackley is sitting on your waiver wire, make the move now as the Pacific Northwest’s best kept secret might not be such a secret for much longer.

On Tuesday night, the Astros traded Jeff Keppinger to the Giants for two relief prospects. While the move looks more significant for the Giants, in Houston it opens the door for Jose Altuve. It’s possible you’ve never heard of the 21-year-old Altuve, as he isn’t a top prospect—not even within Houston’s system—but you probably will remember his sight for years to come, as he stands just 5-foot-7.

Altuve, who started the season in High-A, is jumping to the majors from Double-A because all he has done in the minors is hit. He hit .408/.451/.606 with High-A Lancaster, then .361/.388/.569 with Double-A Corpus Christi. Double-A is often said to be the level of the minors where the men are separated from the boys, and Altuve has played like a man, even if he looks like a boy. Therein lies the tricky part of analyzing whether or not to add Altuve to your fantasy team: there aren’t many comparables or precedents for a player of his size making the majors.

If Altuve is to find success in the majors it will come with his bat. His fielding is okay, but nothing special, and he is just 24 for 38 in steal attempts this season, which leaves a lot to be desired. Brad Mills has said Altuve is his second baseman, though, so the playing time should be ample down the stretch. For that reason, Altuve might be worth the add, if only to avoid feeling regret should he really take the league by storm. Otherwise, if you just must have Altuve and have a free bench spot, take a conservative approach to plugging him into your lineup. It’s difficult to say just how he will perform in the early goings, but if his past is any indication, the guy will hit a little.

A second-half shoulder injury along with some heavy regression to the mean, slowed Jeff Niemann’s progress in 2010. Still, the former first-round pick went 12-8 in 30 games pitched. Deemed healthy in the spring, the beginning of his 2011 campaign looked a lot like the end of last season’s. In the first six starts of the year, Niemann went 1-4 with an ERA near 6.00. A sore back in early May put him back on the disabled list for nearly six weeks.

Upon return from the DL, Niemann has been much improved. His overall record stands at 4-4 with a respectable 3.94 ERA. Even defensive independent metrics like FIP (Fielding Independent Pitching) and xFIP (Expected Fielding Independent Pitching) – two metrics that strip away defense and luck from a pitchers performance – peg him in the 3.90-4.00 range. Considering the first six starts, it has taken some fine work by Niemann since returning to get his overall numbers in line. He has made five starts since being activated going 3-0 with an ERA right around 2.00. His defensive independent marks have him closer to 3.00; however, that’s a above-average peformance regardless.

Before his May vacation, Niemann – who stands 6-foot-9 – was having trouble keeping the ball down and achieving a downward plane in his motion. A slight groundball pitcher throughout his career, he had allowed more flyballs than grounders through six starts. In his five starts since, Niemann’s groundball rate has spiked over 50% thanks to the return of that downward tilt and movement.

In a 16-inning epic on Sunday that ended in a 1-0 loss for his team, the big right-hander had one of his best starts ever. Facing the league’s top offense in the Boston Red Sox, Niemann tossed eight scoreless innings allowing just two walks and two hits while striking out a career-high 10 batters. In his previous start, Niemann allowed just one run in 7.1 innings against another powerful lineup – the New York Yankees – in a notorious hitter’s park – Yankee Stadium.

In addition to his two-seam fastball being effective against the Red Sox, Niemann featured a solid curveball. He threw 31 breaking balls with 21 of them strikes. This year, Niemann’s teammate – James Shields – has had success pitching backwards or throwing off-speed pitches and breaking balls in traditional fastball counts. In an effort to keep the Boston hitters off balance, Niemann threw 10 first-pitch curveballs or changeups on Sunday. Rays’ manager Joe Maddon has dubbed this style of pitching backwards “pitching 2.0.”

Because of his .500 record, the ERA near 4.00, and his time on the DL, Niemann should readily be available in most leagues either on waivers or as a buy-low trade candidate. While he doesn’t project to be much better than the 3.94 ERA he currently has, he could top double-digit wins for a third consecutive season. Also consider the Rays above-average defense behind him; especially if he continues to rack up groundballs in bunches. David Price, James Shields, and Jeremy Hellickson are the most talked about Rays’ starters and with good reason. Meanwhile, Niemann might be the most attractive Tampa Bay starter to acquire in your league right now.

Alex Gordon has been one of the better stories in baseball this season. The former second-overall pick is 27 now, and if he can sustain his first half production, will finish with career-highs in batting average, on-base percentage, slugging percentage, OPS, runs batted in, and runs scored. Not too shabby for a guy who looked to be on his way out of the organization as recently as last season. Don’t get too caught up, though, as there are some warning signs in Gordon’s peripherals.

Anytime a player raises his batting average significantly, an inflated batting average on balls in play is sure to follow. Gordon is no different. Entering this season, he recorded hits on roughly 29 percent of the balls he put into play, yet in 2011 that conversion rate is more than 34 percent. That’s not necessarily a sign that Gordon is all smoke and mirrors, but it doesn’t mean he is hitting the ball better—or at least harder—either.

Gordon had 39 percent of his hits prior to this season go for extra bases, and that number is actually down this season, at 37 percent. His plate appearances aren’t ending in more home runs than normal either. Gordon is seeing a higher percentage of his plate appearances end in extra bases, though, as he has cut into his strikeout and walk rates respectively. That means, while Gordon is hitting more extra base hits on a counting basis, as a rate of his total hits, he has roughly maintained his past rate.

A lot of Gordon’s improvement has come due to singles, which is risky. Gordon’s skill set has not been that of a high-average player in the majors, so be very, very careful moving forward, as he could be in line for some regression.

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